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lib/pkp/classes/i18n/LocaleConversion.php

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+<?php
+
+declare(strict_types=1);
+
+/**
+ * @defgroup i18n I18N
+ * Implements localization concerns such as locale files, time zones, and country lists.
+ */
+
+/**
+ * @file classes/i18n/LocaleConversion.php
+ *
+ * Copyright (c) 2014-2021 Simon Fraser University
+ * Copyright (c) 2000-2021 John Willinsky
+ * Distributed under the GNU GPL v3. For full terms see the file docs/COPYING.
+ *
+ * @class LocaleConversion
+ *
+ * @ingroup i18n
+ *
+ * @brief Provides methods to convert locales from one format to another
+ */
+
+namespace PKP\i18n;
+
+use DateInterval;
+use Exception;
+use Illuminate\Support\Arr;
+use Illuminate\Support\Facades\Cache;
+use PKP\core\Core;
+use PKP\facades\Locale;
+
+class LocaleConversion
+{
+    /** @var string Max lifetime for the ISO639-2b cache. */
+    protected const MAX_ISO6392B_CACHE_LIFETIME = '1 year';
+
+    /**
+     * Get ISO639-2b array
+     *
+     * @throw Exception
+     */
+    protected static function getISO6392b(): array
+    {
+        $iso6392bFile = Core::getBaseDir() . '/' . PKP_LIB_PATH . '/lib/vendor/sokil/php-isocodes-db-i18n/databases/iso_639-2.json';
+        if (!file_exists($iso6392bFile)) {
+            throw new Exception("The ISO639-2b file {$iso6392bFile} does not exist.");
+        }
+        $key = __METHOD__ . 'iso639-2b' . self::MAX_ISO6392B_CACHE_LIFETIME . filemtime($iso6392bFile);
+        $expiration = DateInterval::createFromDateString(static::MAX_ISO6392B_CACHE_LIFETIME);
+        return Cache::remember($key, $expiration, function () use ($iso6392bFile) {
+            return json_decode(file_get_contents($iso6392bFile), true);
+        });
+    }
+
+    /**
+     * Translate the ISO 2-letter language string (ISO639-1) into a ISO compatible 3-letter string (ISO639-2b).
+     */
+    public static function get3LetterFrom2LetterIsoLanguage(?string $iso2Letter): ?string
+    {
+        try {
+            $languages = self::getISO6392b();
+        } catch (Exception $e) {
+            error_log($e->getMessage());
+            return null;
+        }
+        foreach (reset($languages) as $languageRaw) {
+            if (($languageRaw['alpha_2'] ?? null) === $iso2Letter) {
+                return $languageRaw['bibliographic'] ?? $languageRaw['alpha_3'];
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Translate the ISO 3-letter language string (ISO639-2b) into a ISO compatible 2-letter string (ISO639-1).
+     */
+    public static function get2LetterFrom3LetterIsoLanguage(?string $iso3Letter): ?string
+    {
+        try {
+            $languages = self::getISO6392b();
+        } catch (Exception $e) {
+            error_log($e->getMessage());
+            return null;
+        }
+        foreach (reset($languages) as $languageRaw) {
+            if (($languageRaw['bibliographic'] ?? null) === $iso3Letter || $languageRaw['alpha_3'] === $iso3Letter) {
+                return $languageRaw['alpha_2'] ?? null;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Translate the PKP locale identifier into an ISO639-2b compatible 3-letter string.
+     */
+    public static function get3LetterIsoFromLocale(?string $locale): ?string
+    {
+        $iso2Letter = substr($locale, 0, 2);
+        return static::get3LetterFrom2LetterIsoLanguage($iso2Letter);
+    }
+
+    /**
+     * Translate an ISO639-2b compatible 3-letter string into the PKP locale identifier.
+     * This can be ambiguous if several locales are defined for the same language. In this case we'll use the primary locale to disambiguate.
+     * If that still doesn't determine a unique locale then we'll choose the first locale found.
+     */
+    public static function getLocaleFrom3LetterIso(?string $iso3Letter): ?string
+    {
+        $primaryLocale = Locale::getPrimaryLocale();
+
+        $alpha2Candidates = $localeCandidates = [];
+        try {
+            $languages = self::getISO6392b();
+        } catch (Exception $e) {
+            error_log($e->getMessage());
+            return null;
+        }
+        foreach (reset($languages) as $languageRaw) {
+            if (($languageRaw['bibliographic'] ?? null) === $iso3Letter || $languageRaw['alpha_3'] === $iso3Letter) {
+                if (array_key_exists('alpha_2', $languageRaw)) {
+                    $alpha2Candidates[] = $languageRaw['alpha_2'];
+                }
+            }
+        }
+        foreach (Locale::getLocales() as $identifier => $locale) {
+            if (in_array($locale->getIsoAlpha2(), $alpha2Candidates)) {
+                if ($identifier === $primaryLocale) {
+                    // In case of ambiguity the primary locale overrides all other options so we're done.
+                    return $primaryLocale;
+                }
+                $localeCandidates[$identifier] = true;
+            }
+        }
+
+        // Attempts to retrieve the first matching locale which is in the supported list, otherwise defaults to the first found candidate
+        return Arr::first(array_keys(Locale::getSupportedLocales()), fn (string $locale) => $localeCandidates[$locale] ?? false, array_key_first($localeCandidates));
+    }
+
+    /**
+     * Translate the ISO 2-letter language string (ISO639-1) into ISO639-3.
+     */
+    public static function getIso3FromIso1(?string $iso1): ?string
+    {
+        $locale = Arr::first(Locale::getLocales(), fn (LocaleMetadata $locale) => $locale->getIsoAlpha2() === $iso1);
+        return $locale ? $locale->getIsoAlpha3() : null;
+    }
+
+    /**
+     * Translate the ISO639-3 into ISO639-1.
+     */
+    public static function getIso1FromIso3(?string $iso3): ?string
+    {
+        $locale = Arr::first(Locale::getLocales(), fn (LocaleMetadata $locale) => $locale->getIsoAlpha3() === $iso3);
+        return $locale ? $locale->getIsoAlpha2() : null;
+    }
+
+    /**
+     * Translate the PKP locale identifier into an ISO639-3 compatible 3-letter string.
+     */
+    public static function getIso3FromLocale(?string $locale): ?string
+    {
+        $iso1 = substr($locale, 0, 2);
+        return static::getIso3FromIso1($iso1);
+    }
+
+    /**
+     * Translate the PKP locale identifier into an ISO639-1 compatible 2-letter string.
+     */
+    public static function getIso1FromLocale(?string $locale): string
+    {
+        return substr($locale, 0, 2);
+    }
+}